Abacus



3,151,404 A. F. SCHOTT oct. 6, 1964 ABACUS Filed May 16, 1961 v 1i 20 l; INVENmR.

`United States Patent 'ce ma 3,151,404 ABACUS Andrew F. Schott, Brookfield, Wis. (Rte. f1, Green Lake, Wis.) Filed May 16, 1961, Ser. No. 110,564 10 Claims. (Ci. 3533) V"the rods extend and the individual rods are provided with suihcient counters previously to the assembly of the rods in the frame so that when the rods are glued or otherwise permanently secured in the frame, there is no way in which the number of counters upon a rod may be changed or broken counters can be replaced upon a rod.

The result is that rearrangement of the counters, repair of the apparatus, and in fact, the entire assembly operation in the initial construction of the device is complicated and expensive.

It is an object of the invention to simplify and make more economic and effective the original assembly of an abacus; to make in a single piece frame, rods and bars, with braces of great strength so that a satisfactory integral plastic device will result; to make possible and facilitate the replacement of counters in an abacus; and to make possible the rearrangement of counters in an abacus. At the same time, counters of a new shape are more readily moveable upon the rods of an abacus and in combination with rods of a new shape provide, in accord with this invention, a much more satisfactory operation of an abacus.

In the drawings: t

FIGURE 1 is a plan view of an abacus made in accord with my invention.

FIGURE 2 is a section on line 2 2 of FIGURE l, certain of the counters being shown in elevation and certain of them being shown in median, vertical section.

FIGURE 3 is a section on line 3-3 of FIGURE 1.

FIGURE 4 is a perspective of a fragmentary corner portion of an abacus made in accord with my invention, the view showing deformation of ythe -ends of the rods to prevent escape of counters therefrom.

FIGURE 5 is a perspective of a portion of a spring clip used to hold the counters on the rods of my abacus.

FIGURE 6 is a perspective of an individual counter adapted to slide on a rod in my abacus.

FIGURE 7 is a somewhat enlarged sectional view of an alternative form of counter` specially equipped with a spring to bear against a rod to restrain free movement of the counter.

FIGURE 8 is a fragmentary detail showing an alternative means for preventing escape of counters from a rod.

Frame 10 of my abacus uses 'rods 11, 12, 13, 14 and as structural frame members extending between frame end bars 16 and 17. One of these frame end bars which is designated as the base bar-(17) is an angle bar as seen clearly in FIGURE 2. The other frame end bar 16 which will be designated as4 thev top frame bar has rectangular cross section as seen in FIGURES 2 and 4.

The rods `11 to I5 inclusive are frusto triangular in cross section as seen in FIGURE 3, and at each end of each rod lthere is a brace connector 20 secured to the underside of the rod and having generally triangular side elevation. The brace connector extends slightly beyond the end of the rod and olfers a surface normal to the rod against which an end frame member 16 or 17, as the case may be, is secured, preferably integrally.

Since the lower margin of each end frame member is relieved along its entire length except for the provision of downwardly projected feet 21, it is possible to provide brace stops 25 projecting below the brace connectors, but these do not extend downwardly as far as the feet 21 extend. The purpose of these brace stops will be described below.

It will also be noted that the brace Qpnnectors are of such vertical dimension as to support the rod which they serve at such an elevation as to expose the entire end of the rod slightly above the top surface of the end frame member with respect to which it is secured and supported. This is true at each end of each rod 11 to 15 inclusive.

It will further be noted that the top surface of each of the rods have a V-shaped groove extending substantially throughout its length but terminating just short of the extreme end of each rod.

FIGURE 6 shows an individual counter 26, which is in the form of a half toroid, one portion of the complete toroid having been sliced away along a straight line 27, and the walls of the hole are in the shape of a frusto isosceles triangle of such dimensions and angularity as to t, in an easy sliding action, upon one of the rods. It will now be understood why tbe rods are supported slightly higher than the top margins of the end frame members. Counters 26 are readily slidable onto the rods without Contact against the end frame bars.

When the desired number of counters have been slidably positioned onto the respective rods, a spring clip Z8 (see FIGURE 5) may be thrust into position in an assembly operation to retain the counters upon the rods. This spring clip 28 is a somewhat comb-shaped element having backbone 29, and teeth 30 arranged in pairs. The backbone 29 has a vertical dimension somewhat less than the vertical dimension of the feet 21, and when the spring clip is thrust into position shown most clearly in FIGURES 2 and 3, the backbone and the lower portions of the teeth 30 take their positions in iiat face contact against the inside face of an end frame member. When so positioned with the pairs of comb teeth 30 embracing brace connectors, the extended slightly offset ends of the teeth take their positions against the sides of the ends of the rods so as to prevent counters from escaping from the rods. In the iinal upward movement of the spring clip 28, the backbone is caught by the stops 25 so as to hold the backbone against the inside surface of the frame members 16 or 17. This places the spring clip under some tension because or" the oiset upper ends of the comb teeth 30 bearing against the ends of the rods. In this position, the lowermost margin of the spring clip 2S does not bear against any surface which supports the abacus since the feet 21 metal parts of the spring clip in a non-scratching relation to a supporting surface.

As shown in FIGURE 8, it is possible, after the counters have been assembled upon the rods, to momentarily apply heat and pressure at 31 to deform or spread the plastic material of the ends of the rods, thus providing an alternative means for holding the counters in assembled position in sliding relation to the rod.

Since a preferred arrangement of counters upon the rods eifective to carry out rapid mathematical exercises calls for the placement of two counters near one end frame member as shown in FIGURE l, and nine counters upon each rod in relation to the other end frame member, a stop bar is extended across the abacus in position generally as shown so that there is room for the two counters between stop bar 35and end frame member 16, plus suiicient room to displace one or another of such counters along the rod for a distance approximately equaling the thickness of one of the counters;

extend suiiciently to keep the l and the nine counters upon the remaining portion of the rod on the other side of the stop bar have considerable room for movement along the bar as shown.

End bar member 16 is provided with grooves, one in the top margin at 36 and one in the bottom margin 37 so that a decimal cursor 38 of spring material may slide along the rod and be alternatively positionable between any of the pairs of rods to indicate where the decimal point for a particular computation is located.

It will now be seen that prior to the assembly oi' the spring clip 28 into the position shown in FIGURES 2 and 3, counters may be readily slidable onto the rods, and when the counters are positioned on the rods and the spring clips are in position, the counters cannot escape. Counters shaped as shown are readily moveable along' the rods without unnecessary friction and they present no surface extending into such downward relation to the frame rod or brace parts as to contact a supporting surface whereby to cause any dislocation of a counter in an inadvertant manner.

It will be seen in FIGURE 7 that any alternative form of counter is equipped with a bore at 40 of such depth as to'receive a helically coiled spring 4i in position to press outwardly of the bore, were it not for the fact that the margins of ,the bore are slightly deformed to hold the spring in such position as to press a portion of its last convolution against the rod on which it is mounted. Thus there is a certain amount of reluctance against free movement of such a counter. It will tend to remain in place on the rod unless manual pressure is brought to bear to move it along the rod.

It will now be clear that when the desired counters have been slidably installed on the rods made of thermoplastic material, a hot iron or other suitable instrument may swage the ends of the rods to provide a permanent assembly of the frame and counters, Or if the comb shaped clip is used to hold the counters on the rods, the clip 28 is slidably inserted from below with a pair of comb teeth 30 embracing each rod.

Since the teeth are so close together as to call for slight distortion of the comb teeth in order to pass a brace 20 between the teeth, and since the teeth are slightly bowed out of the plane strip from which they are struck (see FIGURE 2), it is necessary to cause the comb to be almost installed, with its teeth against the ends ot the rods before placing stress on the backbone 29 for insertion thereof between brace stop 25 and the particular frame bar 16 or l7 against which the backbone 29 is to bear. Then the clip will snap into place with comb teeth 30 extending in blocking relation to the counters whereby to prevent their escape.

For disassembly, a contrary stress is placed upon the clip whereby to slidaoly release the backbone 29 from the brace stop and then the clip as a whole is readily released to expose the ends ofthe rods.

Thus I have provided an abacus frame formable in one piece as by plastic die forming methods and using the brace connectors 20 not only to provide strong frame relation between the rods and bars, but also to elevate the rods for clearance permitting my new shape of counters to be assembled onto the permanently and integrally related rods. Furthermore, the V-shaped grooves along the top surfaces of the rods provide for extremely smooth and controllable movement of the counters along the rods in a manner not heretofore attainable with uniluted rods.

Cross reference is made to my copending U.S. Patent No. 3,076,272, granted February 5, 1963; the copending application therefor, Serial No. 816,558, filed May 28, 1959, and the abandoned copending application named therein, Serial No. 354,113, filed May l1, 1953.

I claim:

1. In an abacus, a frame having spaced bars, a rod extending between the bars but offset therefrom, a brace connector rigidly connected with a bar and the rod whereby to maintain the rod in odset relation to the bar, and a counter slidably mounted on the rod, said counter having a groove in one side thereof shaped to conform with said rod whereby 4the counter is slidably received on the rod without contacting a bar.

2. In an abacus, a frame having spaced bars, a rod extending between the bars and offset therefrom whereby to completely expose the ends of the rod, brace connector within the frame immediately adjacent the bars attached to the rod and one of the bars, and counters slidably mounted on the. rod.

3. TheV abacus of claim 2 in which said counters are provided with a side opening groove to receive the rod.

4. The abacus of claim 2 in which the rod is grooved substantially throughout its length whereby to facilitate movement of the counter along the rod.

5. In an abacus, spaced bars and spaced rods for a frame, brace connectors integrally joining thel rods and bars and positioned to hold the rods in position exposing the ends of the rods immediately adjacent the bars within the frame, said rods having a geometric conliguration in cross section presenting a small dimension adjacent the bar, and counters grooved to provide groove walls complementary to said geometric configuration whereby the counters are receivable upon the rods, and a clip shaped to embrace a connector and positioned to block the end of the rod adjacent a bar whereby to prevent the sliding escape of a counter from the rod.

6. An abacus having a plurality of rods shaped frustro triangularly in cross section with a small dimension along corresponding longitudinal margins, stop equipped brace connectors comprising right triangular members respectively having legs integrally joined with said longitudinal margins of said rods and extending beyond the ends of said rods, a bar secured integrally to the other right triangular legs of the brace connectors at right angles to the rods and positioned to expose the end of the rods, a comb-shaped clip having a backbone receivable against the stops and resilient comb teeth braced against the end of the rods, and counters slidably mounted on the rods,

` but prevented from escape therefrom by said clip teeth.

7. The abacus of claim 6 wherein the rods each have a grooved longitudinal surface presenting'edges of such groove along a margin of the rod opposite the marginI having said small dimension.

8. The abacus of claim 7 in which the counters are each provided with a resiliently pressed member positioned to bear against the margins of the groove in the rod whereby to frictionally resist movement of counter along the rod.

9.l An abacus comprising a plurality of rods, end bars and means connecting the ends of said rods in offset relation to said bars to permit sliding counters off the rods clear of the bars, a stop on each rod intermediate its ends, stops on both ends of each rod and counters slidable on said rods between the ends stops and the intermediate stops, the stops at at least one of the ends of the rods being removable to facilitate changing the number of counters on the rods between said one end and the intermediate stops.

10. rThe abacus of claim 9 in which said removable stops comprise a comb-shaped clip having adjacent teeth which embrace the respective rods and project into the path of counters on the rods.

References Cited in the tile of this patent UNITED STATES PATENTS 232,482 Fitch sept. 21, 1880 1,028,212 Hegewald June 4, 1912 2,803,069 Struna Aug. 20, 1957 3,076,272 Schott Feb. 5, 1963 FOREIGN PATENTS 103,081 Austria Apr. 10, 1926 

1. IN AN ABACUS, FRAME HAVING SPACED BARS, A ROD EXTENDING BETWEEN THE BARS BUT OFFSET THEREFROM, A BRACE CONNECTOR RIGIDLY CONNECTED WITH A BAR AND THE ROD WHEREBY TO MAINTAIN THE ROD IN OFFSET RELATION TO THE BAR, AND A COUNTER SLIDABLY MOUNTED ON THE ROD, SAID COUNTER 